- Email: [email protected]
Effect of mood state on anticipatory postural adjustments
Neuroscience Letters 370 (2004) 65–68
Effect of mood state on anticipatory postural adjustments Kazuyoshi Kitaokaa,b , Risa Itoc , Hideo Arakid , Hiroyoshi Seia,∗ , Yusuke Moritaa a
Department of Integrative Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Kuramoto 3-18-15, Tokushima 770-8503, Japan b Department of Molecular Nutrition, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan c Department of Psychology, Faculty of Human Life Sciences, Tokushima Bunri University, Tokushima 770-8514, Japan d Department of Human Sciences, Faculty of Integrated Arts and Sciences, The University of Tokushima, Tokushima 770-8502, Japan Received 10 May 2004; received in revised form 6 July 2004; accepted 29 July 2004
Abstract Static postural control has been demonstrated to link with psychological state. However, the effect of psychological state on dynamic postural control remains unclear. In this study, we examined the effect of mood state on anticipatory postural adjustment (APA), one of the most important functions for dynamic postural control. Fourteen healthy male subjects performed unilateral arm elevation tasks after completing a Profile of Mood States (POMS) questionnaire. Mood state measured by POMS and the latency or amplitude of the APA in the ventral muscles (rectus femoris, tibialis anterior) of the lower limb showed significant negative correlations. The correlation between the mood state and APA amplitude in the soleus was found to be significantly positive. There were significant negative correlations between the mood state and reaction-time. These findings suggest that it is possible that dynamic postural control is affected by mood state. © 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Anticipatory postural adjustment; Postural control; Mood state; Human
Anxiety disorder has been repeatedly reported to associate with balance function disorder [9,14,17]. In addition, previous studies on healthy subjects have shown that psychological state affects postural control. High anxiety modifies the location and frequency of the center of pressure (COP) in the anterior–posterior axis [12,16]. Bolmont et al. [3] demonstrated that a deterioration of mood state, measured by Profile of Mood States (POMS), affects motor balance performance and the subject’s ability to use input from either the somatosensory, visual or vestibular system to maintain balance. These studies, however, focused on static postural control, i.e., spontaneous body sway. While executing the various tasks, our posture is continuously controlled by dynamic postural control such as anticipatory postural adjustment (APA). APA is feed-forward
∗
Corresponding author. Tel.: +81 88 633 9251; fax: +81 88 633 9251. E-mail address: [email protected] (H. Sei).
0304-3940/$ – see front matter © 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.neulet.2004.07.088
postural control observed as changes in the activity of postural muscles that occur prior to a voluntary action [2,13]. When we lift an arm while standing, we contract the muscles of our legs before those of the arms so that the shift in center of mass will not cause us to fall over [8]. The aim of this study was to clarify the existence of a relationship between dynamic postural control and psychological factors by examining the influence of mood state on APA. Fourteen healthy male subjects, aged 19–33 years (mean ± S.D.: 22.1 ± 4.7 years), participated in this study. Informed consent was obtained for all subjects. This study was performed according to the guidelines stated in the declaration of Helsinki. Mood states were assessed using the Japanese version of the POMS (Kanekoshobo, Tokyo, Japan), which classifies the following six mood factors: Tension–Anxiety, Depression, Anger–Hostility, Vigor, Fatigue, and Confusion. The questionnaire was completed before APA recording,
66
K. Kitaoka et al. / Neuroscience Letters 370 (2004) 65–68
and the raw score of each factor was converted into a t-score. A surface electromyogram (EMG) was recorded from the following muscles on the right side of the body using disposable electrodes (blue sensor electrode P-00-S, Medicotest A/S, Denmark): anterior deltoid (AD), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and soleus (SOL). RF and TA are the ventral muscles, while BF and SOL are the dorsal muscles of the lower limb. AD was prime mover in reaction tasks performed in this study. The electrodes were placed over the muscle bellies and the distance between the two electrodes was set for 3 cm. EMG signals were sampled using an “Eplyzer” data acquisition system (Kissei Comtec, Tokyo, Japan) through an EEG amplifier (SYNAFIT 1000, San-ei Medical System, Tokyo, Japan). The signals from the electrodes were band-pass filtered (5–200 Hz) and rectified prior to sampling. In order to measure the APA activity, the subjects were ordered to perform reaction tasks (lifting their right arm) at imperative signal which was presented after warning signal in the normal standing posture. Both signals consisted of pure tone stimulus (duration: 100 ms, frequency: 1 kHz, intensity: 90 dB), and the interval was set for 2 s. The reaction-time was determined as the interval between the imperative signal and the time when the right arm passed a vinyl chloride plate equipped with a strain gauge. The vinyl chloride plate was placed in the sagittal plane at shoulder level at the maximum reach distance. The experiment consisted of two conditions, each consisting of 20 trials. In one condition, the subject was instructed to elevate his right arm at his own pace (self-paced; SP). In another condition, the subject was told to elevate his arm as fast as possible (reaction-time; RT). It is well known that fast limb movements, which cause strong segmental acceleration and inertial force, provoke an increase of APA amplitude and duration, and delayed APA onset [5–7,10]. We, therefore, expected that the effect of mood state on APAs would be exaggerated in the RT condition compared to the SP condition. Fig. 1 shows the procedure used for quantification of the APAs. Digitized EMG data were viewed off-line on a computer monitor and the first visible burst of AD muscle was determined by visual inspection. This point was considered as start point of the activation in the prime mover AD, and defined as “time zero” (t0) for APA analysis. The time interval between t0 and first visible deflection (muscle burst) of the BF was determined as the APA latency. Since APA precedes the activation of prime mover, APA latency was negative value. The following formula was used to estimate APA amplitudes [15] EMG = A − 3 B where A is the anticipatory activity: an integral EMG activity from −100 ms to +50 ms with respect to t0 and B, background activity: an integral EMG activity from −500 ms to −450 ms with respect to t0.
Fig. 1. Schematic illustration of the procedure used to quantify APA. All the muscles were recorded in the right part of the body: AD, RF, BF, TA, and SOL. The motor onset (t0) was determined at the onset of AD burst. APA latency was measured by the time interval between t0 and the onset of BF burst. APA amplitudes of postural muscle were calculated with the integrated EMG for the periods indicated as gray zones. Anticipatory activity and background activity: see text.
Statistical analysis was performed using the Spearman coefficient of correlation to assess the correlation between APA latency, amplitude or reaction-time and the t-scores for the POMS. The coefficients of correlation between APA latency and scores of mood state are detailed in Table 1. In the RT condition, The APA latency was negatively correlated with the score for Tension–Anxiety (r = −0.655, P < 0.05), Depression (r = −0.553, P < 0.05) and Anger–Hostility (r = −0.633, P < 0.05) significantly. In the SP condition, the APA latency showed significant negative correlation with only Tension–Anxiety score (r = −0.584, P < 0.05). Table 2 shows the correlation between APA amplitude and mood state. In the SP condition, several significant correlations were found. The RF muscle amplitude showed significant negative correlations with scores for Anger–Hostility (r = −0.710, P < 0.01) and Confusion (r = −0.574, P < 0.05). The APA amplitude of TA muscle was negatively correlated with the score of Anger–Hostility (r = −0.541, P < 0.05). On the other hand, the APA amplitude of SOL muscle was positively correlated with the Depression score significantly (r = 0.543, P < 0.05). However, in the RT condition, no significant correlation was found. The correlation between the reaction-time and mood state are summarized in Table 3. In the RT condition, the reactionTable 1 Correlation between mood state and APA latency
Tension–Anxiety Depression Anger–Hostility Vigor Fatigue Confusion
RT
SP
−0.655∗ −0.553∗ −0.633∗ 0.299 −0.369 0.277
−0.584∗ −0.415 −0.218 0.363 0.179 0.024
RT: reaction-time condition; SP: self-paced condition, see text. ∗ P < 0.05.
K. Kitaoka et al. / Neuroscience Letters 370 (2004) 65–68
67
Table 2 Correlation between mood state and APA amplitude RT
Tension–Anxiety Depression Anger–Hostility Vigor Fatigue Confusion
SP
RF
BF
TA
SOL
RF
BF
TA
SOL
0.177 0.132 −0.154 −0.204 0.155 −0.344
0.287 0.437 0.248 −0.413 0.045 −0.044
−0.225 −0.119 −0.378 0.086 −0.269 −0.345
0.038 −0.092 −0.169 0.105 −0.049 −0.193
−0.502 −0.514 −0.710∗∗ 0.141 −0.298 −0.574∗
0.148 0.268 0.152 −0.193 0.052 −0.073
−0.249 0.048 −0.541∗ −0.224 −0.293 −0.459
0.300 0.543∗ 0.158 −0.492 −0.014 0.062
RF, BF, TA, and SOL: same as in Fig. 1; RT and SP: same as in Table 1. ∗ P < 0.05. ∗∗ P < 0.01.
time was positively correlated with the Confusion score (r = 0.545, P < 0.05). In the SP condition, the correlation between the Tension–Anxiety score and the reaction-time was significantly positive (r = 0.560, P < 0.05). The present study demonstrates that mood states, determined by POMS, are significantly correlated with the amplitude or latency of APAs in normal subjects. Our data suggests the possibility that there is a relationship between dynamic postural control and psychological factors. Adkin et al. [1] reported that fear of falling modifies APAs. Our data coincide with their findings. The negative correlations between APA latency and mood state indicate that the APA occurs earlier when the mood states are more deteriorated. A subject with more deteriorated mood state showed a lower amplitude on RF and TA, and a greater amplitude on SOL. APAs are known to appear as an inhibition of tonic activity on the SOL muscle in movement of a forward COP shift (cf. arm elevation, jump movement) [4,11]. These findings, therefore, indicate that the deterioration of mood state affects the EMG latency or activity of not particular leg muscles, but the total set of muscles involved in APA. The reaction-time was increased with deterioration of mood state. Previous studies have proposed that a decrease in reaction-time causes a delay in APA occurrence and an increase in APA amplitude [7,10]. These reports may be in agreement with the findings reported here. Although it is in the opposite direction, APA disturbance with the deterioration of the mood state may provoke a delay in reaction-time. It is noteworthy that, in the RT condition, significant correlations between APA and mood state were found in latency, Table 3 Correlation between mood state and reaction-time
Tension–Anxiety Depression Anger–Hostility Vigor Fatigue Confusion RT and SP: same as in Table 1. ∗ P < 0.05.
RT
SP
0.227 0.088 0.352 0.043 0.198 0.545∗
0.560∗ 0.317 0.275 −0.353 0.096 0.308
while they were seen in amplitudes in the SP condition. We selected two conditions (SP, RT) in this study, because we considered that the effects of mood state on APAs would appear stronger in the RT condition with faster limb movement [5–7,10]. However, the APA change by deteriorated mood state in this study was more complicated as shown in Tables 1–3. Our two conditions may have the differences, not only in mechanical condition, but also in intentional and/or motivational condition. It is presumed that the complexity of the difference between the two conditions might have contributed to the results in our study. Further experiments are needed to clarify the relationships between the effects of mood state on APA and postural tasks. In conclusion, our results show that the deterioration in mood state is linked with the APA function. Not only static body sway, but also dynamic postural control during movement is affected by mood state.
Acknowledgment This work was partially supported by a Grant-in-Aid for Scientific Research from the 21st Century COE Program, Human Nutritional Science on Stress Control, Tokushima, Japan.
References [1] A.L. Adkin, J.S. Frank, M.G. Carpenter, G.W. Peysar, Fear of falling modifies anticipatory postural control, Exp. Brain Res. 143 (2002) 160–170. [2] V.Y. Belenkiy, V.S. Gurfinkel, Y.I. Pal’tsev, Elements of control of voluntary movements, Biofizika 10 (1967) 135–141. [3] B. Bolmont, P. Gangloff, A. Vouriot, P.P. Perrin, Mood states and anxiety influence abilities to maintain balance control in healthy human subjects, Neurosci. Lett. 329 (2002) 96–100. [4] S. Bouisset, M. Zattara, A sequence of postural movements precedes voluntary movement, Neurosci. Lett. 22 (1981) 263–270. [5] S. Bouisset, J. Richardson, M. Zattara, Are amplitude and duration of anticipatory postural adjustments identically scaled to focal movement parameters in human? Neurosci. Lett. 278 (2000) 153–156. [6] S. Bouisset, J. Richardson, M. Zattara, Do anticipatory postural adjustments occurring in different segments of the postural chain follow the same organizational rule for different task movement velocities,
68
[7]
[8]
[9]
[10]
[11]
K. Kitaoka et al. / Neuroscience Letters 370 (2004) 65–68 independently of the inertial load value? Exp. Brain Res. 132 (2000) 79–86. S. De Wolf, H. Slijper, M.L. Latash, Anticipatory postural adjustments during self-paced and reaction-time movements, Exp. Brain Res. 121 (1998) 7–19. C. Ghez, J. Krakauer, The organization of movement, in: E.R. Kandel, J.H. Schwartz, T.M. Jessell (Eds.), Principles of Neural Science, McGraw-Hill Companies, New York, 2000, pp. 653–673. R.G. Jacob, J.M. Furman, J.D. Durrant, S.M. Turner, Surface dependence: a balance control strategy in panic disorder with agoraphobia, Psychosom. Med. 59 (1997) 323–330. W.A. Lee, T.S. Buchanan, M.W. Rogers, Effects of arm acceleration and behavioral conditions on the organization of postural adjustments during arm flexion, Exp. Brain Res. 66 (1987) 257–270. A. Le Pellec, B. Maton, Anticipatory postural adjustments depend on final equilibrium and task complexity in vertical high jump movements, J. Electromyogr. Kinesiol. 10 (2000) 171–178.
[12] B.E. Maki, W.E. Mcllroy, Influence of arousal and attention on the control of postural sway, J. Vestib. Res. 6 (1996) 53–59. [13] J. Massion, Movement, posture and equilibrium: interaction and coordination, Prog. Neurobiol. 38 (1992) 35–56. [14] G. Perna, A. Dario, D. Caldirola, B. Stefania, A. Cesarani, L. Bellodi, Panic disorder: the role of the balance system, J. Psychiatr. Res. 35 (2001) 279–286. [15] T. Shiratori, M.L. Latash, The roles of proximal and distal muscles in anticipatory postural adjustments under asymmetrical perturbations and during standing on rollerskates, Clin. Neurophysiol. 111 (2000) 613–623. [16] M. Wada, N. Sunaga, M. Nagai, Anxiety affects postural sway of the antero-posterior axis in college students, Neurosci. Lett. 302 (2001) 157–159. [17] L. Yardley, J. Britton, S. Lear, J. Bird, L.M. Luxon, Relationship between balance system function and agoraphobic avoidance, Behav. Res. Ther. 33 (1995) 435–439.
Effect of mood state on anticipatory postural adjustments Kazuyoshi Kitaokaa,b , Risa Itoc , Hideo Arakid , Hiroyoshi Seia,∗ , Yusuke Moritaa a
Department of Integrative Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Kuramoto 3-18-15, Tokushima 770-8503, Japan b Department of Molecular Nutrition, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan c Department of Psychology, Faculty of Human Life Sciences, Tokushima Bunri University, Tokushima 770-8514, Japan d Department of Human Sciences, Faculty of Integrated Arts and Sciences, The University of Tokushima, Tokushima 770-8502, Japan Received 10 May 2004; received in revised form 6 July 2004; accepted 29 July 2004
Abstract Static postural control has been demonstrated to link with psychological state. However, the effect of psychological state on dynamic postural control remains unclear. In this study, we examined the effect of mood state on anticipatory postural adjustment (APA), one of the most important functions for dynamic postural control. Fourteen healthy male subjects performed unilateral arm elevation tasks after completing a Profile of Mood States (POMS) questionnaire. Mood state measured by POMS and the latency or amplitude of the APA in the ventral muscles (rectus femoris, tibialis anterior) of the lower limb showed significant negative correlations. The correlation between the mood state and APA amplitude in the soleus was found to be significantly positive. There were significant negative correlations between the mood state and reaction-time. These findings suggest that it is possible that dynamic postural control is affected by mood state. © 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Anticipatory postural adjustment; Postural control; Mood state; Human
Anxiety disorder has been repeatedly reported to associate with balance function disorder [9,14,17]. In addition, previous studies on healthy subjects have shown that psychological state affects postural control. High anxiety modifies the location and frequency of the center of pressure (COP) in the anterior–posterior axis [12,16]. Bolmont et al. [3] demonstrated that a deterioration of mood state, measured by Profile of Mood States (POMS), affects motor balance performance and the subject’s ability to use input from either the somatosensory, visual or vestibular system to maintain balance. These studies, however, focused on static postural control, i.e., spontaneous body sway. While executing the various tasks, our posture is continuously controlled by dynamic postural control such as anticipatory postural adjustment (APA). APA is feed-forward
∗
Corresponding author. Tel.: +81 88 633 9251; fax: +81 88 633 9251. E-mail address: [email protected] (H. Sei).
0304-3940/$ – see front matter © 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.neulet.2004.07.088
postural control observed as changes in the activity of postural muscles that occur prior to a voluntary action [2,13]. When we lift an arm while standing, we contract the muscles of our legs before those of the arms so that the shift in center of mass will not cause us to fall over [8]. The aim of this study was to clarify the existence of a relationship between dynamic postural control and psychological factors by examining the influence of mood state on APA. Fourteen healthy male subjects, aged 19–33 years (mean ± S.D.: 22.1 ± 4.7 years), participated in this study. Informed consent was obtained for all subjects. This study was performed according to the guidelines stated in the declaration of Helsinki. Mood states were assessed using the Japanese version of the POMS (Kanekoshobo, Tokyo, Japan), which classifies the following six mood factors: Tension–Anxiety, Depression, Anger–Hostility, Vigor, Fatigue, and Confusion. The questionnaire was completed before APA recording,
66
K. Kitaoka et al. / Neuroscience Letters 370 (2004) 65–68
and the raw score of each factor was converted into a t-score. A surface electromyogram (EMG) was recorded from the following muscles on the right side of the body using disposable electrodes (blue sensor electrode P-00-S, Medicotest A/S, Denmark): anterior deltoid (AD), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and soleus (SOL). RF and TA are the ventral muscles, while BF and SOL are the dorsal muscles of the lower limb. AD was prime mover in reaction tasks performed in this study. The electrodes were placed over the muscle bellies and the distance between the two electrodes was set for 3 cm. EMG signals were sampled using an “Eplyzer” data acquisition system (Kissei Comtec, Tokyo, Japan) through an EEG amplifier (SYNAFIT 1000, San-ei Medical System, Tokyo, Japan). The signals from the electrodes were band-pass filtered (5–200 Hz) and rectified prior to sampling. In order to measure the APA activity, the subjects were ordered to perform reaction tasks (lifting their right arm) at imperative signal which was presented after warning signal in the normal standing posture. Both signals consisted of pure tone stimulus (duration: 100 ms, frequency: 1 kHz, intensity: 90 dB), and the interval was set for 2 s. The reaction-time was determined as the interval between the imperative signal and the time when the right arm passed a vinyl chloride plate equipped with a strain gauge. The vinyl chloride plate was placed in the sagittal plane at shoulder level at the maximum reach distance. The experiment consisted of two conditions, each consisting of 20 trials. In one condition, the subject was instructed to elevate his right arm at his own pace (self-paced; SP). In another condition, the subject was told to elevate his arm as fast as possible (reaction-time; RT). It is well known that fast limb movements, which cause strong segmental acceleration and inertial force, provoke an increase of APA amplitude and duration, and delayed APA onset [5–7,10]. We, therefore, expected that the effect of mood state on APAs would be exaggerated in the RT condition compared to the SP condition. Fig. 1 shows the procedure used for quantification of the APAs. Digitized EMG data were viewed off-line on a computer monitor and the first visible burst of AD muscle was determined by visual inspection. This point was considered as start point of the activation in the prime mover AD, and defined as “time zero” (t0) for APA analysis. The time interval between t0 and first visible deflection (muscle burst) of the BF was determined as the APA latency. Since APA precedes the activation of prime mover, APA latency was negative value. The following formula was used to estimate APA amplitudes [15] EMG = A − 3 B where A is the anticipatory activity: an integral EMG activity from −100 ms to +50 ms with respect to t0 and B, background activity: an integral EMG activity from −500 ms to −450 ms with respect to t0.
Fig. 1. Schematic illustration of the procedure used to quantify APA. All the muscles were recorded in the right part of the body: AD, RF, BF, TA, and SOL. The motor onset (t0) was determined at the onset of AD burst. APA latency was measured by the time interval between t0 and the onset of BF burst. APA amplitudes of postural muscle were calculated with the integrated EMG for the periods indicated as gray zones. Anticipatory activity and background activity: see text.
Statistical analysis was performed using the Spearman coefficient of correlation to assess the correlation between APA latency, amplitude or reaction-time and the t-scores for the POMS. The coefficients of correlation between APA latency and scores of mood state are detailed in Table 1. In the RT condition, The APA latency was negatively correlated with the score for Tension–Anxiety (r = −0.655, P < 0.05), Depression (r = −0.553, P < 0.05) and Anger–Hostility (r = −0.633, P < 0.05) significantly. In the SP condition, the APA latency showed significant negative correlation with only Tension–Anxiety score (r = −0.584, P < 0.05). Table 2 shows the correlation between APA amplitude and mood state. In the SP condition, several significant correlations were found. The RF muscle amplitude showed significant negative correlations with scores for Anger–Hostility (r = −0.710, P < 0.01) and Confusion (r = −0.574, P < 0.05). The APA amplitude of TA muscle was negatively correlated with the score of Anger–Hostility (r = −0.541, P < 0.05). On the other hand, the APA amplitude of SOL muscle was positively correlated with the Depression score significantly (r = 0.543, P < 0.05). However, in the RT condition, no significant correlation was found. The correlation between the reaction-time and mood state are summarized in Table 3. In the RT condition, the reactionTable 1 Correlation between mood state and APA latency
Tension–Anxiety Depression Anger–Hostility Vigor Fatigue Confusion
RT
SP
−0.655∗ −0.553∗ −0.633∗ 0.299 −0.369 0.277
−0.584∗ −0.415 −0.218 0.363 0.179 0.024
RT: reaction-time condition; SP: self-paced condition, see text. ∗ P < 0.05.
K. Kitaoka et al. / Neuroscience Letters 370 (2004) 65–68
67
Table 2 Correlation between mood state and APA amplitude RT
Tension–Anxiety Depression Anger–Hostility Vigor Fatigue Confusion
SP
RF
BF
TA
SOL
RF
BF
TA
SOL
0.177 0.132 −0.154 −0.204 0.155 −0.344
0.287 0.437 0.248 −0.413 0.045 −0.044
−0.225 −0.119 −0.378 0.086 −0.269 −0.345
0.038 −0.092 −0.169 0.105 −0.049 −0.193
−0.502 −0.514 −0.710∗∗ 0.141 −0.298 −0.574∗
0.148 0.268 0.152 −0.193 0.052 −0.073
−0.249 0.048 −0.541∗ −0.224 −0.293 −0.459
0.300 0.543∗ 0.158 −0.492 −0.014 0.062
RF, BF, TA, and SOL: same as in Fig. 1; RT and SP: same as in Table 1. ∗ P < 0.05. ∗∗ P < 0.01.
time was positively correlated with the Confusion score (r = 0.545, P < 0.05). In the SP condition, the correlation between the Tension–Anxiety score and the reaction-time was significantly positive (r = 0.560, P < 0.05). The present study demonstrates that mood states, determined by POMS, are significantly correlated with the amplitude or latency of APAs in normal subjects. Our data suggests the possibility that there is a relationship between dynamic postural control and psychological factors. Adkin et al. [1] reported that fear of falling modifies APAs. Our data coincide with their findings. The negative correlations between APA latency and mood state indicate that the APA occurs earlier when the mood states are more deteriorated. A subject with more deteriorated mood state showed a lower amplitude on RF and TA, and a greater amplitude on SOL. APAs are known to appear as an inhibition of tonic activity on the SOL muscle in movement of a forward COP shift (cf. arm elevation, jump movement) [4,11]. These findings, therefore, indicate that the deterioration of mood state affects the EMG latency or activity of not particular leg muscles, but the total set of muscles involved in APA. The reaction-time was increased with deterioration of mood state. Previous studies have proposed that a decrease in reaction-time causes a delay in APA occurrence and an increase in APA amplitude [7,10]. These reports may be in agreement with the findings reported here. Although it is in the opposite direction, APA disturbance with the deterioration of the mood state may provoke a delay in reaction-time. It is noteworthy that, in the RT condition, significant correlations between APA and mood state were found in latency, Table 3 Correlation between mood state and reaction-time
Tension–Anxiety Depression Anger–Hostility Vigor Fatigue Confusion RT and SP: same as in Table 1. ∗ P < 0.05.
RT
SP
0.227 0.088 0.352 0.043 0.198 0.545∗
0.560∗ 0.317 0.275 −0.353 0.096 0.308
while they were seen in amplitudes in the SP condition. We selected two conditions (SP, RT) in this study, because we considered that the effects of mood state on APAs would appear stronger in the RT condition with faster limb movement [5–7,10]. However, the APA change by deteriorated mood state in this study was more complicated as shown in Tables 1–3. Our two conditions may have the differences, not only in mechanical condition, but also in intentional and/or motivational condition. It is presumed that the complexity of the difference between the two conditions might have contributed to the results in our study. Further experiments are needed to clarify the relationships between the effects of mood state on APA and postural tasks. In conclusion, our results show that the deterioration in mood state is linked with the APA function. Not only static body sway, but also dynamic postural control during movement is affected by mood state.
Acknowledgment This work was partially supported by a Grant-in-Aid for Scientific Research from the 21st Century COE Program, Human Nutritional Science on Stress Control, Tokushima, Japan.
References [1] A.L. Adkin, J.S. Frank, M.G. Carpenter, G.W. Peysar, Fear of falling modifies anticipatory postural control, Exp. Brain Res. 143 (2002) 160–170. [2] V.Y. Belenkiy, V.S. Gurfinkel, Y.I. Pal’tsev, Elements of control of voluntary movements, Biofizika 10 (1967) 135–141. [3] B. Bolmont, P. Gangloff, A. Vouriot, P.P. Perrin, Mood states and anxiety influence abilities to maintain balance control in healthy human subjects, Neurosci. Lett. 329 (2002) 96–100. [4] S. Bouisset, M. Zattara, A sequence of postural movements precedes voluntary movement, Neurosci. Lett. 22 (1981) 263–270. [5] S. Bouisset, J. Richardson, M. Zattara, Are amplitude and duration of anticipatory postural adjustments identically scaled to focal movement parameters in human? Neurosci. Lett. 278 (2000) 153–156. [6] S. Bouisset, J. Richardson, M. Zattara, Do anticipatory postural adjustments occurring in different segments of the postural chain follow the same organizational rule for different task movement velocities,
68
[7]
[8]
[9]
[10]
[11]
K. Kitaoka et al. / Neuroscience Letters 370 (2004) 65–68 independently of the inertial load value? Exp. Brain Res. 132 (2000) 79–86. S. De Wolf, H. Slijper, M.L. Latash, Anticipatory postural adjustments during self-paced and reaction-time movements, Exp. Brain Res. 121 (1998) 7–19. C. Ghez, J. Krakauer, The organization of movement, in: E.R. Kandel, J.H. Schwartz, T.M. Jessell (Eds.), Principles of Neural Science, McGraw-Hill Companies, New York, 2000, pp. 653–673. R.G. Jacob, J.M. Furman, J.D. Durrant, S.M. Turner, Surface dependence: a balance control strategy in panic disorder with agoraphobia, Psychosom. Med. 59 (1997) 323–330. W.A. Lee, T.S. Buchanan, M.W. Rogers, Effects of arm acceleration and behavioral conditions on the organization of postural adjustments during arm flexion, Exp. Brain Res. 66 (1987) 257–270. A. Le Pellec, B. Maton, Anticipatory postural adjustments depend on final equilibrium and task complexity in vertical high jump movements, J. Electromyogr. Kinesiol. 10 (2000) 171–178.
[12] B.E. Maki, W.E. Mcllroy, Influence of arousal and attention on the control of postural sway, J. Vestib. Res. 6 (1996) 53–59. [13] J. Massion, Movement, posture and equilibrium: interaction and coordination, Prog. Neurobiol. 38 (1992) 35–56. [14] G. Perna, A. Dario, D. Caldirola, B. Stefania, A. Cesarani, L. Bellodi, Panic disorder: the role of the balance system, J. Psychiatr. Res. 35 (2001) 279–286. [15] T. Shiratori, M.L. Latash, The roles of proximal and distal muscles in anticipatory postural adjustments under asymmetrical perturbations and during standing on rollerskates, Clin. Neurophysiol. 111 (2000) 613–623. [16] M. Wada, N. Sunaga, M. Nagai, Anxiety affects postural sway of the antero-posterior axis in college students, Neurosci. Lett. 302 (2001) 157–159. [17] L. Yardley, J. Britton, S. Lear, J. Bird, L.M. Luxon, Relationship between balance system function and agoraphobic avoidance, Behav. Res. Ther. 33 (1995) 435–439.